Liberal Democrats who fail to back a Bill to give voters a referendum on
European Union membership will be undermining democracy, David Cameron has
suggested.

The Prime Minister said enshrining in law that an “in-out” vote must be held by the end of 2017 would contribute to restoring “democratic consent” for the work of the EU. Asked whether he would be urging Nick Clegg, the Deputy Prime Minister, to back the Conservative Party’s referendum Bill in the Commons next week, Mr Cameron said “everyone” should support the measure.

The Lib Dem and Labour Party leaderships have indicated they will allow their MPs not to attend the Commons next Friday, when the Bill is being debated. This is likely to mean that the measure passes the Commons but Labour has said it will use a variety of delaying tactics to block it in the House of Lords.

Both Labour and the Lib Dems oppose the legislation although Mr Clegg has conceded that a referendum is likely.

Asked at the EU summit in Brussels whether he wanted the Lib Dems to back the Bill, Mr Cameron said: “I want everyone to support this Bill because I think it is the right thing for Britain. We need a changed relationship to reflect what has happened in the eurozone and reflect the wishes and needs of countries like Britain.

“But also we have got to try and restore connection with people’s ordinary democratic consent.”

Mr Clegg, the Lib Dem leader, has refused to allow government time to debate the measures, forcing the Conservatives to use a back-bench MP, James Wharton, to bring forward the legislation.

Labour has stressed that Ed Miliband, the party leader, would do everything in his power to prevent the referendum plan becoming law. Other Labour figures including Ed Balls, the shadow chancellor, have said the party must not rule out offering voters a referendum in the next manifesto.

Mr Cameron criticised European Union leaders, saying he has to be ready for “an ambush at any time”.

The Prime Minister warned his counterparts he would “lock and load” his gun with a bullet “up the spout” to fight Britain’s corner.

He was speaking after a late-night “ambush” by the French president, François Hollande, who tried to cut Britain’s budget rebate of £3.1 billion by £1.5 billion.